Researchers say Earth is entering a sixth mass extinction event

A research team says highly conservative estimates prove we are entering a sixth mass extinction event(Credit: NASA/Terry Virts)

While there is still much conjecture about the causes of some mass extinctions, it is generally believed that they can occur when a biosphere under long-term stress is subjected to a short-term shock. In 1982, Jack Sepkoski and David M. Raup
published a paper identifying five mass extinction events throughout Earth's history. Now a team of researchers claims that we are entering a sixth mass extinction event, which threatens our very existence.

As ever more species
face extinction, we lose the vital ecosystem services they provide,
such as honeybee crop pollination. For its continued existence,
mankind is reliant upon an untold plethora of species that maintain
the status quo. As they disappear, that existence becomes
increasingly fragile.

The paper entitled Accelerated modern human–induced species losses: Entering the sixth mass extinction, which was
co-authored by Paul Ehrlich, a Professor of Population Studies in
biology and senior fellow at the Stanford Woods Institute for the
Environment, draws on fossil records of vertebrate species and an
abundance of data from other sources, combining them to create a
baseline extinction rate for periods when there was no mass
extinction event underway. Predicated on this baseline, the
researchers were able to estimate that the current rates of
vertebrate extinction is up to 114 times greater than that of the
baseline.

According to the Union for Conservation of Nature, at this point
roughly 41 percent of amphibian species and 26 percent of mammal
species are in serious danger of extinction. Alarmingly, extinction
rates are now at their highest point since the Cretaceous-Paleogene
extinction event some 66 million years
ago.

The paper's authors
stress that their findings are conservative in nature, and that the
reality of the situation could be much worse. While conducting the
study, the researchers even set the baseline extinction rate at twice
the value of estimates widely used in previous analyses.Amongst the causes for the
increased extinction rates are mankind's
destruction of animals' natural habitats, and carbon emission driven
climate change.

According to Ehrlich
and his colleagues there is still hope, but in order to avoid dire
consequences, we must embark upon a comprehensive regime of wildlife
and habitat conservation. The researchers also warn that the window for change is
growing ever slimmer.

"If it is allowed to continue, life would take many millions of years to recover, and our species itself would likely disappear early on," said lead author Gerardo Ceballos of the Universidad Autónoma de México.